Vacuum tube



Dec. 22j, 1931.

v. Kf zwoRYKlN VACUUM TUBE Filed Oct. 9. 1926 III INVENTOR WITNESSES:

VlcldimrKZwoYYkin l ATTORNEY i Patented Dec. 22, 1931 UNITEDr STATESPATENT oFFlcE- y i 'VLADIMIR IK. ZWORYKIN, 0F SWISSVALE, PENNSYLVANIA,ASSIGNOB TO WESTING- 'HOUSE marmo. a VANIA MANUFACTURING COMPANY, ACORPORTION 0F PENNSYL- ,VACUUM TUBE Application led October 9, 1926.Serial No. 140,485.

y Myinvention relates to vacuum-tube de vices, and more particularly todevlces of the type ,in which' a metallic vapor. is either purposely orunavoidably present, and devices of the type in which the operationthereof gives riseto vapors that tend to condense and form conductivecoatings.

It is an object of my invention to provide an improvedelectrode-supporting element for use in vacuum-tube devices.

Another object of my invention is to provide an electrode-supportingelement having means incorporated therein for preventing metallic, orother deposits, from forming leakage paths between contiguouselectrodes.

Another object of my invention is to provide an electrode-supportingelement having a shield incorporated therewith for preventing thedeposition of metallic or other conductive coatings thereon.

Still another and more specific object of my invention is to provide avacuum-tube electrode-supporting press comprising means forautomatically removing conductive deposits as fast as they form inlocations where the leakage caused thereby is disadvantageous.

In substantially all of the present day thermionic tube devices, and inmany photoelectric cells,it has become customary to support theelectrodes from a single glass element generally known as a press. Theelectrode supports are generally rather closely spaced where they mergefrom the press and, when in use, a potential difference is usuallyapplied between certain of them.

. In devices, .such as photoelectric cells makmg use of potassium,considerable difficulty has been experienced from leakage betweenelectrodes, caused by the deposition of vola' tilized potassium on thepress. It is often noted, in addition, that the use of magnesium as agetter is quite likely to cause an undesirable ilm of magnesium tobe sodeposited on the press as to form leakage paths. Material volatilizedfrom incandescent filaments also occasionally condenses on the press andinterferes with the proper functioning of the device. l

According to my invention, an electrodesupporting press is provided witha shield for preventing the deposition of conducting material thereon. Iinterpose also a device be.

tween contiguous electrodes'for automatically -removing a conductingfilm as fast as it forms,

the energy for actuating the cleaning device being derived frommovements of the tube, as a whole, when handled.

The novel features which are considered characteristic of this inventionare set forth with particularity in the appended claims.

The invention itself, however, both as to its organization and itsmethod of operation, together with further objects' and advantagesthereof will best be understood by reference to the followingdescription, taken in connection with the accompanying drawings, inwhich, l

Fig. 1 is a. sectional view of a photoelectric cell embodying apreferred form of my invention, y i

`Fig. 2 is a, sectional view along a line corresponding to the lineII--II of Fig. 1, and

Figs. 3 and'4 are sectional views ofalternative forms of the cleaningdevice.

In order to more clearly explain the a plication of my invention to avacuum-tu device, I have shown, in Fig. 1, the .manner in which it maybe applied to a photoelectric cell containing potassium vapor. The cellcomprises a glass envelope 1 having one portion thereof enlarged toaccommodate a photoelectrically active cathode 2 and a cooperating anode3. The end 4 of the envelope opposite the enlarged portion is providedwith a re-entrant press, or stem 5, through which passes an electrodesupport 6 aiiixed to the cathode, and an additional support 7 for ananode 8. In the specific form of tube chosen for illustration, the anode8 may obviously be merely a continuation of the supporting standard,ywhile it is also feasible to utilize a deposit on the surface of theenvelope as the cathode.

At the point where the cathode support 6 emerges from the press, it issurrounded bg a small tube-like element 9 continuous wit the pressmaterial. The upper edge 11 of this element is ground to a smoothsurface, and a short iece 120i tubing rests thereon and` surrounds thecathodesupport 6.

The lower edge of the short, detached, piece 12 of tubing is preferablyslightly roughened, for a purpose that later will be explained.

The anode support 7 is also surrounded by a fixed tube-like element,13,and is similarly provided with a detached, short piece 14.- oftubing.

In order to prevent, in so far as practicable, the deposition ofconductive material on the press adjacent to the points of emergence ofthe electrode supports, a shield 15 is provided to entirely surround thepress 5. The electrode supports 6 and 7 Nextend through a restrictedopening 16 in the upper portion of the shield, which opening is madesufficiently small to prevent the detached portions l2 and 14 of tubingfrom passing therethrough.

When in use, it is obvious that the photoelectric cell will benecessarily subjected to a certain amount of handling. The detachedportions of tubing, being somewhat larger in internal diameter than theelectrode supports, will move around on the supporting tubes 9 and 13and will exert a grinding and ycleaning action on any conductivematerial that may be deposited thereon. The upper edges of the fixedtubes thus being kept clean, electrical leakage between the electrodesupports is prevented.

It is not essential that the fixed tubes rising from the press beprovided with upper edges at right angles to the tube axis, it havingbeen found that Athe modifications illustrated in Figs. 3 and 4 areequally effective.

Referring specifically to Fig. 8, the electrode support 21 is surroundedby a fixed tube 22 having a rounded upper edge 23. A detached tube, orbead 24, is loosely mounted around the electrode support, and rests onthe rounded surface of the fixed tube. When the device is handled, thedetached tube, being free to move relatively to the fixed tube, exerts agrinding, or cleaning action on the rounded surface thereof.

In Fig. 3, I have shown the lower edge of .the detached tube or beadsubstantially at right angles to the axis of the tube, whichconstruction causes the cleaning action to be tcccmplished by the innersharp edge of the The lower end of the bead may also, if desired, bebeveled as illustrated in Fig. 4, which permits it to make'contact withan appreciable amount of the surface of the fixed tube. Either thelatter modification, or that illustrated in Fig. 3, is eective to lkeepthe upper portion of the fixed tube from becoming covered by aconductive coating.

Although I have illustrated and described certain specific embodimentsof my invention, I am aware that obvious modifications thereof will beapparent to those skilled in the art, and my invention accordingly isnot to be limited except insofar as is necessitated by the prior art andby the spirit of the appended claims.

I claim as my invention:

1. In combination, a discharge device comprising a plurality ofstandards adapted to support electrodes, an element in which saidstandards are mounted, and means, including an element actuated bymovements of the device as a whole, for keeping free Afrom conductivedeposits a portion of the standardsupporting element.

2. In combination, a. press, a plurality of electrodes supported fromsaid press, means for shielding said press from the deposition ofconductive material, and means for automatically cleaning a portion ofthe. press between electrodes. f

In testimony whereof, I have hereunto subscribed my name this 2nd day ofOctober,

VLADIMIR K. ZWORYKIN.

